My house is about 49 years old (one bathroom) and water is supplied by a well. My water supply setup consists of a: Myers 1/2 H.P. Jet Pump (set at 60psi), Challenger 14 Gallon Bladder Tank Accumulator, Culligan Water Softener (added last year), Whirlpool 40 Gallon Water Heater, and 1/2" PVC piping running throughout the house. It seems that ever since I added the water softener the pressure went down. I realize pressure is not supplied by the pump, the pump supplies volume, and pressure is resistance to flow. The water heater has 1/2" CPVC going into and out of it, the water softener has 3/4" PVC going in and 1/2" PVC teed off going under the house and into the water heater. Could this be the root of the problem and would it be advisable to run a 3/4" PVC trunk line (for both hot and cold water) under the house to correct my low water pressure problem?
You can run PVC for cold water only, and you really shouldn't have any PVC within a foot or two of the water heater due to hot water expansion back into the cold water supply line. You must use CPVC only for hot water.
If your pump is set at 40-60 psi cut-on/cut-off, the pressure tank bladder should be set at two psi below the cut-on pressure (38 psi).
To check the pressure tank, turn off the pump, drain the water pressure off, and check the tank pressure with a tire gauge. It should be 38 psi. If it isn't and it needs air, air it up with a bicycle pump or portable air tank or compressor to the 38.
If your 1/2 hp pump is pumping up to the 60 psi cut-off, and cuts back on when it drains down to 40, what does it build up to while the water is running?
Larger pipe will help deliver more volume and less resistance, but I tend to think that you may need to go to a 3/4 hp pump to maintain increased pressure.